This proposal is for matching funds to purchase a new PET System to replace our NeuroPET system that was manufactured in 1985. Our current NeuroPET system has been the primary imaging system for our funded research studies of the biochemical and biological mechanisms of normal human brain development and neuronal plasticity, including the compensatory reorganization of the brain following injury, disease or surgery. It has been critical to our studies of developmental disorders, pediatric and adult epilepsy, Alzheimer's, Parkinson's, Huntington's, depression/mania, and cancer of the brain. This system, which is one of a kind, is very old for a high tech device. Most of the critical components are no longer manufactured, and repair is dependent upon rebuilt devices, that frequently fail shortly after installation. Although this NeuroPET system was state of the art for the mid to late 80's, it is no longer competitive with the state of the art for the mid to late 90's. Without a state of the art NeuroPET system, it would be difficult for us to obtain data of an accuracy and precision that would be appropriate for these funded research projects. In addition, since all currently available commercial PET systems are capable of imaging the torso, the new system would be able to supplement our capabilities in heart imaging and 3-D whole body studies. These projects involve approximately $3.2 million in NIH and $3.4 million in DoE research funds per year, and most of these projects require a PET system. Most of the brain imaging studies either cannot be performed with our current whole body system, or the quality of the study is inferior. We have raised 82 % of the required funding by obtaining a significant discount on the equipment from the vendor, and obtaining $700,000 from the Simon Fund to apply to this purchase. The existing research grants will provide the necessary maintenance and operating support for the PET system. The administration of the PET system is carried out by a Resource Allocation Committee (RAC) that consists of the PIs of the major grants and representatives of the technology components (i.e., PET scanners, cyclotron, chemistry, and animal laboratories). This administrative configuration has been in effect for 15 years and has efficiently allocated the resources of the PET systems and other major instruments.